Process for producing α-olefin polymer

ABSTRACT

An α-olefin polymer having extremely high stereoregularity, exhibiting excellent fluidity and containing a decreased amount of catalyst residues in the polymer can be obtained industrially advantageously in accordance with a process for producing an α-olefin polymer which comprises homopolymerizing an α-olefin or copolymerizing two or more α-olefins in the presence of (A) a solid catalyst component comprising magnesium, titanium and a halogen, (B) an organoaluminum compound having a content of hydroaluminum compounds of 0.1% by weight or smaller and (C) an organozinc compound. 
     A block copolymer of propylene comprising a homopolymer portion exhibiting high fluidity and a copolymer portion having a high molecular weight can be obtained in accordance with a process for producing a block copolymer of propylene which comprises polymerizing propylene in the presence of (A) a solid catalyst component comprising a titanium compound and an electron-donating agent, (B) an organoaluminum compound and (C) an organozinc compound to produce crystalline polypropylene and copolymerizing propylene and at least one of ethylene and α-olefins having 4 or more carbon atoms in the presence of the produced crystalline polypropylene.

TECHNICAL FIELD

The present invention relates to a process for producing an α-olefinpolymer and, more particularly, to a process for producing an α-olefinpolymer which efficiently provides an olefin polymer having extremelyhigh stereoregularity and exhibiting excellent fluidity and a processfor producing a block copolymer of propylene and at least one ofethylene and α-olefins having 4 or more carbon atoms.

BACKGROUND ART

Since olefin polymers, in particular polypropylene (hereinafter referredto as PP, occasionally), are crystalline macromolecular compounds, theolefin polymers exhibit excellent rigidity, tensile strength, heatresistance, chemical resistance, optical properties and workability andhave low specific gravities. Therefore, the olefin polymers are widelyused in various fields such as injection molded articles, containers andpackaging materials.

As the catalyst system for polymerizing α-olefins, many catalystscomprising a solid catalyst component, an organoaluminum compound and,where necessary, an electron-donating compound have been disclosed. Thesolid catalyst component comprises magnesium, titanium, halogen elementsand, where necessary, an electron-donating compound. When an α-olefinpolymer is produced using such a catalyst, in general, hydrogen is usedas the chain transfer agent. However, this process has a drawback inthat hydrogen must be added in a great amount in order to obtain anα-olefin polymer exhibiting high fluidity and, as the result, thestereoregularity deteriorates or productivity decreases due to adecrease in the monomer concentration in the polymerization field.

As described above, it is the general practice that the amount ofhydrogen as the chain transfer agent during the polymerization isincreased to improve fluidity of the polymer from the standpoint ofworkability. However, since the resistance of a reactor to pressure islimited, the concentration of the monomer which can be placed into thereactor decreases due to the increase in the concentration of hydrogen.This causes a decrease in the efficiency of the catalyst and an economicdisadvantage arises.

Thus, the present invention has a first object of providing a processfor industrially advantageously producing an α-olefin polymer havingextremely high stereoregularity, exhibiting excellent fluidity andcontaining a decreased amount of catalyst residues in the polymer.

A block copolymer of propylene (hereinafter referred to as block PP,occasionally) is produced, in general, in accordance with a processcomprising producing a homopolymer of propylene by polymerization ofpropylene, followed by producing a copolymer by copolymerization withother momoners. The properties required for block PP are mechanicalproperties derived from the homopolypropylene and impact resistance inan excellent balance. It is also required that the molding property,appearance and elongation are excellent. It is known that suchrequirements can be satisfied by a structure having a homopolymerportion exhibiting excellent fluidity and a copolymer portion having arelatively high molecular weight.

To enhance fluidity of the homopolymer portion, in general, the amountof hydrogen used as the chain transfer agent is increased during thepolymerization. However, when hydrogen used in the homopolymerization inthe first stage affects the condition of the copolymerization in thesecond stage, in other words, when hydrogen is not removed or is onlypartially removed between the first stage and the second stage, anincreased amount of hydrogen in the stage of the homopolymerizationcauses a decrease in the molecular weight of the copolymer portion dueto an increase in the amount of hydrogen in the reactor used in thecopolymerization of the second stage and block PP having the desiredimpact resistance cannot be obtained. To improve the impact resistanceof block PP, it is necessary that hydrogen be removed completely betweenthe first stage and the second stage and the additional facilities beinstalled for this purpose. Moreover, the inner pressure ofpolymerization apparatuses increases when the amount of hydrogen isincreased during the polymerization. Since the resistance of thepolymerization apparatuses to pressure is limited, the amount ofhydrogen used during the polymerization is naturally limited. In thiscase, fluidity of the obtained homopolypropylene is limited and block PPhaving the desired properties cannot be obtained.

When fluidity of the homopolymer portion in block PP is increased bydecomposition of the polymer, the fluidity expected from the melt index(MI) cannot be obtained. Moreover, a problem arises in that physicalproperties such as impact resistance deteriorate since the molecularweight of the block portion also decreases.

Therefore, development of a process for producing a homopolymer having ahigh fluidity without a decrease in the molecular weight of thecopolymer portion or an increase in the inner pressure of the reactorhas been desired.

The present invention has a second object of providing a process forefficiently producing a block polypropylene comprising a homopolymerportion exhibiting a high fluidity and a copolymer portion having a highmolecular weight.

DISCLOSURE OF THE INVENTION

As the result of intensive studies by the present inventors to overcomethe above problems on the process for producing an α-olefin polymer,with respect to the first object, it was found that an α-olefin polymercould be industrially advantageously produced by using an organozinccompounds as the essential component and an organoaluminum compoundhaving a small content of hydroaluminum compounds.

As the first invention, the following processes for producing anα-olefin polymer are provided.

[1] A process for producing an α-olefin polymer which compriseshomopolymerizing an α-olefin or copolymerizing two or more α-olefins ina presence of (A) a solid catalyst component comprising magnesium,titanium and a halogen, (B) an organoaluminum compound having a contentof hydroaluminum compounds of 0.1% by weight or smaller and (C) anorganozinc compound.

[2] A process for producing an α-olefin polymer described above in [1],wherein the solid catalyst component of component (A) further comprisesan electron-donating agent.

[3] A process for producing an α-olefin polymer described above in anyof [1] and [2], wherein the organozinc compound of component (C) is anorganozinc compound represented by a general formula:ZnR¹R²wherein R¹ and R² each represent a hydrocarbon group having 1 to 10carbon atoms and may represent a same group or different groups.

[4] A process for producing an α-olefin polymer described above in anyof [1] to [3], wherein the homopolymerization or the copolymerization isconducted in a further presence of (D) an electron-donating compound.

[5] A process for producing an α-olefin polymer described above in anyof [1] to [4], wherein the organoaluminum compound has a content ofhydroaluminum compounds of 0.01% by weight or smaller.

With respect to the second object, it was found that, when an organozinccompound was present in the catalyst for polymerization of propylenecomprising a titanium compound, an electron-donating agent and anorganoaluminum compound during the homopolymerization in the firststage, the molecular weight could be reduced to a great degree so that ahomopolymer of propylene exhibiting excellent fluidity could be obtainedand the molecular weight showed almost no decrease in thecopolymerization of the second stage.

In accordance with this process, it is not necessary that the amount ofhydrogen is increased and a homopolymer of propylene exhibiting desiredfluidity can be produced under a condition of a low partial pressure ofhydrogen, for example, in a slurry process in which a polymer ofpropylene is produced while propylene is dissolved in an inerthydrocarbon solvent or in a gas phase process in which a polymer ofpropylene is produced by reaction of propylene in the gas phase. Whenblock PP is produced, the decrease in the molecular weight of thecopolymer portion in the second stage can be prevented. For example, ina bulk process in which a polymer of propylene is produced in a liquidpropylene, the pressure of hydrogen can be decreased and a homopolymerof propylene exhibiting excellent fluidity can be easily produced usinga small amount of hydrogen even when the resistance to pressure in theprocess is limited.

As the second invention, the following processes for producing a blockcopolymer of propylene are provided.

[1] A process for producing a block copolymer of propylene whichcomprises polymerizing propylene in a presence of (A) a solid catalystcomponent comprising a titanium compound and an electron-donating agent,(B) an organoaluminum compound and (C) an organozinc compound to producecrystalline polypropylene and copolymerizing propylene and at least oneof ethylene and α-olefins having 4 or more carbon atoms in a presence ofthe produced crystalline polypropylene.

[2] A process for producing a block copolymer of propylene describedabove in [1], wherein the solid catalyst component of component (A)further comprises a magnesium compound.

[3] A process for producing a block copolymer of propylene describedabove in any of [1] and [2], wherein the crystalline polypropylene isproduced in a further presence of (D) an electron-donating compound.

[4] A process for producing a block copolymer of propylene describedabove in [3], wherein the electron-donating compound is an organosiliconcompound.

[5] A process for producing a block copolymer of propylene describedabove in any of [3] and [4], wherein the solid catalyst component ofcomponent (A) is obtained by bringing the titanium compound and amagnesium compound into contact with each other in a presence of theelectron-donating agent at a temperature of 120 to 150° C. and washingan obtained product with an inert solvent at a temperature of 100 to150° C.

[6] A process for producing a block copolymer of propylene describedabove in [5], wherein the solid catalyst component of component (A) isobtained by bringing the titanium compound and the magnesium compoundinto contact with each other in a presence of the electron-donatingagent and a silicon compound at a temperature of 120 to 150° C. andwashing an obtained product with an inert solvent at a temperature of100 to 150° C.

[7] A process for producing a block copolymer of propylene describedabove in any of [1] to [6], wherein the organozinc compound of component(C) is an organozinc compound represented by a general formula:ZnR¹R²wherein R¹ and R² each represent a hydrocarbon group having 1 to 10carbon atoms and may represent a same group or different groups.

[8] A process for producing a block copolymer of propylene describedabove in any of [1] to [7], wherein (E) an electron-donating substanceis added before or during the copolymerization of propylene and at leastone of ethylene and α-olefins having 4 or more carbon atoms.

THE MOST PREFERRED EMBODIMENT TO CARRY OUT THE INVENTION

In accordance with the processes for producing an α-olefin polymer ofthe present invention (the first invention and the second invention), anα-olefin is homopolymerized or copolymerized in the presence of (A) asolid catalyst component, (B) an organoaluminum compound, (C) anorganozinc compound and, where necessary, (D) an electron-donatingcompound.

In the first invention, (a) magnesium, (b) titanium and (c) a halogenatom are used as the essential components for (A) the solid catalystcomponent and, where necessary, (d) an electron-donating agent is used.An organoaluminum compound having a content of hydroaluminum compoundsof 0.1% by weight or smaller is used as (B) the organo-aluminumcompound.

In the second invention, (b) a titanium compound and (d) anelectron-donating agent are used as the essential components for (A) thesolid catalyst component and, where necessary, (a) a magnesium compoundand (e) a silicon compound are used. Propylene is polymerized in thepresence of the above components and a crystalline polypropylene isproduced. Then, in the presence of the polypropylene produced above,propylene and at least one of ethylene and α-olefins having 4 or morecarbon atoms are copolymerized and a block copolymer of propylene isproduced. As (E) an electron-donating substance which is added before orduring the copolymerization of propylene and at least one of ethyleneand α-olefins having 4 or more carbon atoms, (d) the electron-donatingagent or (D) the electron-donating compound is used.

The components of the catalyst for polymerization of olefins in thepresent invention and the process for preparing the catalyst will bedescribed in the following.

(A) The Solid Catalyst Component

(a) Magnesium Compound

It is necessary that component (A) of the first invention comprisesmagnesium. Therefore, a magnesium compound is used for preparation ofcomponent (A).

For component (A) of the second invention, a magnesium compound is usedwhere necessary.

The magnesium compound is not particularly limited. Magnesium compoundsrepresented by general formula (I):MgR³R⁴  (I)are preferably used.

In general formula (I), R³ and R⁴ represent a hydrocarbon group, a grouprepresented by OR⁵, R⁵ representing a hydrocarbon group, or a halogenatom. Examples of the hydrocarbon group represented by R³ and R⁴ includealkyl groups having 1 to 12 carbon atoms, cycloalkyl groups, aryl groupsand aralkyl groups. Examples of the group represented by OR⁵ includegroups in which R⁵ represents an alkyl group having 1 to 12 carbonatoms, a cycloalkyl group, an aryl group or an aralkyl group. Examplesof the halogen atom include chlorine atom, bromine atom, iodine atom andfluorine atom. R³ and R4 may represent the same group or differentgroups.

Examples of the magnesium compound represented by general formula (I)include alkylmagnesiums and arylmagnesiums such as dimethylmagnesium,diethylmagnesium, diisopropylmagnesium, dibutylmagnesium,dihexylmagnesium, dioctylmagnesium, ethylbutylmagnesium,diphenylmagnesium and dicyclohexylmagnesium; alkoxymagnesiums andaryloxymagnesiums such as dimethoxymagnesium, diethoxymagnesium,dipropoxymagnesium, dibutoxymagnesium, dihexyloxymagnesium,dioctoxymagnesium, diphenoxymagnesium and dicyclohexyloxymagnesium;alkylmagnesium halides and arylmagnesium halides such as ethylmagnesiumchloride, butylmagnesium chloride, hexylmagnesium chloride,isopropylmagnesium chloride, isobutylmagnesium chloride,t-butylmagnesium chloride, phenylmagnesium bromide, benzylmagnesiumchloride, ethylmagnesium bromide, butylmagnesium bromide,phenyl-magnesium chloride and butylmagnesium iodide; alkoxymagnesiumhalides and aryloxymagnesium halides such as butoxymagnesium chloride,cyclohexyloxymagnesium chloride, phenoxymagnesium chloride,ethoxy-magnesium bromide, butoxymagnesium bromide and ethoxymagnesiumiodide; and magnesium halides such as magnesium chloride, magnesiumbromide and magnesium iodide.

Among these magnesium compounds, magnesium halides alkoxy-magnesiums,alkylmagnesiums and alkylmagnesium halides are preferable from thestandpoint of the polymerization activity and the stereoregularity.

The above magnesium compounds can be prepared from metallic magnesium orcompound containing magnesium.

For example, the above magnesium compound can be prepared by bringingmetallic magnesium into contact with a halogen and an alcohol.

Examples of the halogen include iodine, chlorine, bromine and fluorine.Among these halogens, iodine is preferable. Examples of the alcoholinclude methanol, ethanol, propanol, butanol and cyclohexanol, octanol.

As another example, the above magnesium compound can be prepared bybringing an alkoxymagnesium represented by Mg(OR⁶)₂, R⁶ representing ahydrocarbon group having 1 to 20 carbon atoms, into contact with ahalide.

Examples of the halide include silicon compounds of component (e) whichwill be described later, silicon tetrachloride, silicon tetrabromide,tin tetrachloride, tin tetrabromide and hydrogen chloride. Among thesecompounds, silicon tetrachloride is preferable from the standpoint ofthe polymerization activity and the stereoregularity. Preferableexamples of the hydrocarbon group represented by R⁶ include alkyl groupssuch as methyl group, ethyl group, propyl group, isopropyl group, butylgroup, isobutyl group, hexyl group and octyl group; cyclohexyl group;alkenyl groups such as allyl group, propenyl group and butenyl group;aryl groups such as phenyl group, tolyl group and xylyl group; andaralkyl groups such as phenetyl group and 3-phenylpropyl group. Amongthese groups, alkyl groups having 1 to 10 carbon atoms are preferable.

The above magnesium compounds may be supported on a support such assilica, alumina and polystyrene.

The above magnesium compound may be used singly or in combination of twoor more and may comprise other elements such as halogens such as iodine,silicon and aluminum or electron-donating agents such as alcohols,ethers and esters.

(b) Titanium Compound

In the first and second inventions, it is necessary that component (A)comprises titanium. Therefore, a titanium compound is used in thepreparation of component (A).

The titanium compound is not particularly limited. Titanium compoundsrepresented by general formula (II):TiX¹ _(p)(OR⁷)_(4-p)  (II)are preferably used.

In general formula (II), X¹ represents a halogen atom, which ispreferably chlorine atom or bromine atom and more preferably chlorineatom. R⁷ represents a hydrocarbon group which may be a saturated groupor an unsaturated group, may be a linear group, a branched group orcyclic group and may have hetero atoms such as sulfur, nitrogen, oxygen,silicon and phosphorus. It is preferable that R⁷ represents ahydrocarbon group having 1 to 10 carbon atoms, more preferably an alkylgroup, an alkenyl group, a cycloalkenyl group, an aryl group or anaralkyl group and most preferably a linear or branched alkyl group. Whena plurality of groups represented by OR⁷ are present, the plurality ofgroups may be the same with or different from each other. Examples ofthe group represented by R⁷ include methyl group, ethyl group, n-propylgroup, isopropyl group, n-butyl group, sec-butyl group, isobutyl group,n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-decylgroup, allyl group, butenyl group, cyclopentyl group, cyclohexyl group,cyclohexenyl group, phenyl group, tolyl group, benzyl group and phenetylgroup. p represents an integer of 0 to 4.

Examples of the titanium compound represented by the above generalformula (II) include tetraalkoxytitaniums such as tetramethoxytitanium,tetraethoxytitanium, tetra-n-propoxytitanium, tetraisopropoxytitanium,tetra-n-butoxytitanium, tetraisobutoxytitanium,tetracyclohexyloxytitanium and tetraphenoxytitanium; titaniumtetrahalides such as titanium tetrachloride, titanium tetrabromide andtitanium tetraiodide; alkoxytitanium trihalides such as methoxytitaniumtrichloride, ethoxytitanium trichloride, propoxytitanium trichloride,n-butoxytitanium trichloride and ethoxytitanium tribromide;dialkoxytitanium dihalides such as dimethoxytitanium dichloride,diethoxytitanium dichloride, diisopropoxytitanium dichloride,di-n-propoxytitanium dichloride and diethoxytitanium dibromide; andtrialkoxytitanium monohalides such as tiimethoxytitanium chloride,triethoxytitanium chloride, triisopropoxytitanium chloride,tri-n-propoxytitanium chloride and tri-n-butoxytitanium chloride. Amongthese compounds, titanium compounds having a greater number of halogenatoms are preferable and titanium tetrachloride is more preferable fromthe standpoint of the polymerization activity. The titanium compound maybe used singly or in combination of two or more.

(c) Halogen Atom

The halogen contained in the solid catalyst component of component (A)in the first invention is, in general, supplied from the magnesiumcompound and the titanium compound described above.

(d) Electron-Donating Agent

Examples of the electron-donating agent, which is an optional componentin the first invention and the essential component in the secondinvention, include electron-donating agents containing oxygen such asalcohols, phenols, ketones, aldehydes, carboxylic acids, malonic acid,esters of organic acids and inorganic acids and ethers such asmonoethers, diethers and polyethers; and electron-donating agentscontaining nitrogen such as ammonia, amines, nitriles and isocyanates.Examples of the above organic acid include carboxylic acids and,specifically, malonic acid.

Among the above electron-donating agents, esters of polybasic carboxylicacids and polyethers are preferable. Esters of aromatic polybasiccarboxylic acids are more preferable. From the standpoint of thepolymerization activity, diesters of aromatic dibasic carboxylic acidsare most preferable. As the organic group in the ester portion, alinear, branched or cyclic aliphatic hydrocarbon group is preferable.

Examples of the diester of a dibasic aromatic carboxylic acid includedialkyl esters of dicarboxylic acids. Examples of the dicarboxylic acidinclude phthalic acid, naphthalene-1,2-dicarboxylic acid,naphthalene-2,3-dicarboxylic acid,5,6,7,8-tetrahydronaphthalene-1,2-dicarboxylic acid,5,6,7,8-tetrahydronaphthalene-2,3-dicarboxylic acid,indan-4,5-dicarboxylic acid and indan-5,6-dicarboxylic acid. Examples ofthe alkyl group in the dialkyl ester portion include methyl group, ethylgroup, n-propyl group, isopropyl group, n-butyl group, isobutyl group,t-butyl group, n-pentyl group, 1-methylbutyl group, 2-methylbutyl group,3-methylbutyl group, 1,1-dimethylpropyl group, 1-methylpentyl group,2-methylpentyl group, 3-methylpentyl group, 4-methylpentyl group,1-ethylbutyl group, 2-ethylbutyl group, n-hexyl group, cyclohexyl group,n-heptyl group, n-octyl group, n-nonyl group, 2-methylhexyl group,3-methylhexyl group, 4-methylhexyl group, 2-ethylhexyl group,3-ethylhexyl group, 4-ethylhexyl group, 2-methylpentyl group,3-methylpentyl group, 2-ethylpentyl group and 3-ethylpentyl group.

Among these compounds, diesters of phthalic acid are preferable. It ispreferable that the organic group in the ester portion is a linear orbranched aliphatic hydrocarbon group having 4 or more carbon atoms fromthe standpoint of the activity and the stereoregularity. Preferableexamples of the diester of phthalic acid include di-n-butyl phthalate,diisobutyl phthalate and di-n-heptyl phthalate.

Examples of the polyether include compounds represented by the followinggeneral formula (III):

wherein n represents an integer of 2 to 10, R⁸ to R¹⁵ each represent asubstituent having at least one element selected from carbon, hydrogen,oxygen, halogens, nitrogen, sulfur, phosphorus, boron and silicon, R¹¹and R¹² may represent the same substituent or different substituents,any substituents among the substituents represented by R⁸ to R¹⁵,preferably substituents represented by R¹¹ and R¹², may from a ringwhich is not a benzene ring and the main chain may have atoms other thancarbon atom. Examples of the polyether compound represented by generalformula (III) include 2-(2-ethylhexyl)-1,3-dimethoxypropane,2-isopropyl-1,3-dimethoxypropane, 2-butyl-1,3-dimethoxypropane,2-s-butyl-1,3-dimethoxypropane, 2-cyclohexyl-1,3-dimethoxypropane,2-phenyl-1,3-dimethoxypropane, 2-cumyl-1,3-dimethoxypropane,2-(2-phenylethyl)-1,3-dimethoxypropane,2-(2-cyclohexylethyl)-1,3-dimethoxypropane,2-(p-chlorophenyl)-1,3-dimethoxypropane,2-(diphenylmethyl)-1,3-dimethoxy-propane,2-(1-naphthyl)-1,3-dimethoxypropane,2-(2-fluorophenyl)-1,3-dimethoxypropane,2-(1-decahydronaphthyl)-1,3-dimethoxypropane,2-(p-t-butylphenyl)-1,3-dimethoxypropane,2,2-dicyclohexyl-1,3-dimethoxy-propane,2,2-dicyclopentyl-1,3-dimethoxypropane,2,2-diethyl-1,3-dimethoxypropane, 2,2-dipropyl-1,3-dimethoxypropane,2,2-diisopropyl-1,3-dimethoxypropane, 2,2-dibutyl-1,3-dimethoxypropane,2-methyl-2-propyl-1,3-dimethoxypropane,2-methyl-2-benzyl-1,3-dimethoxypropane,2-methyl-2-ethyl-1,3-dimethoxypropane,2-methyl-2-isopropyl-1,3-dimethoxypropane,2-methyl-2-phenyl-1,3-dimethoxypropane,2-methyl-2-cyclohexyl-1,3-dimethoxypropane,2,2-bis(p-chlorophenyl)-1,3-dimethoxy-propane,2,2-bis(2-cyclohexylethyl)-1,3-dimethoxypropane,2-methyl-2-isobutyl-1,3-dimethoxypropane,2-methyl-2-(2-ethylhexyl)-1,3-dimethoxy-propane,2,2-diisobutyl-1,3-dimethoxypropane, 2,2-diphenyl-1,3-dimethoxypropane,2,2-dibenzyl-1,3-dimethoxypropane,2,2-bis(cyclohexyl-methyl)-1,3-dimethoxypropane,2,2-diisobutyl-1,3-diethoxypropane, 2,2-diisobutyl-1,3-dibutoxypropane,2-isobutyl-2-isopropyl-1,3-dimethoxy-propane,2-(1-methylbutyl)-2-isopropyl-1,3-dimethoxypropane,2-(1-methylbutyl)-2-s-butyl-1,3-dimethoxypropane,2,2-di-s-butyl-1,3-dimethoxypropane,2,2-di-t-butyl-1,3-dimethoxypropane,2,2-dineopentyl-1,3-dimethoxypropane,2-isopropyl-2-isopentyl-1,3-dimethoxypropane,2-phenyl-2-isopropyl-1,3-dimethoxypropane,2-phenyl-2-s-butyl-1,3-dimethoxypropane,2-benzyl-2-isopropyl-1,3-dimethoxypropane,2-benzyl-2-s-butyl-1,3-dimethoxypropane,2-phenyl-2-benzyl-1,3-dimethoxypropane,2-cyclopentyl-2-isopropyl-1,3-dimethoxypropane,2-cyclopentyl-2-s-butyl-1,3-dimethoxypropane,2-cyclohexyl-2-isopropyl-1,3-dimethoxypropane,2-cyclohexyl-2-s-butyl-1,3-dimethoxypropane,2-isopropyl-2-s-butyl-1,3-dimethoxypropane,2-cyclohexyl-2-cyclohexylmethyl-1,3-dimethoxy-propane,2,3-diphenyl-1,4-diethoxybutane, 2,3-dicyclohexyl-1,4-diethoxybutane,2,2-benzyl-1,4-diethoxybutane, 2,3-dicyclohexyl-1,4-diethoxybutane,2,3-diisopropyl-1,4-diethoxybutane,2,2-bis(p-methylphenyl)-1,4-dimethoxybutane,2,3-bis(p-chlorophenyl)-1,4-dimethoxybutane,2,3-bis(p-fluorophenyl)-1,4-dimethoxybutane,2,4-diphenyl-1,5-dimethoxypentane, 2,5-diphenyl-1,5-dimethoxyhexane,2,4-diisopropyl-1,5-dimethoxypentane,2,4-diisobutyl-1,5-dimethoxypentane, 2,4-diisoamyl-1,5-dimethoxypentane,3-methoxymethyltetrahydrofuran, 3-methoxymethyldioxane,1,3-diisobutoxypropane, 1,2-diisobutoxypropane, 1,2-diisobutoxyethane,1,3-diisoamyloxypropane, 1,3-diisoneopentyloxy-ethane,1,3-dineopentyloxypropane, 2,2-tetramethylene-1,3-dimethoxy-propane,2,2-pentamethylene-1,3-dimethoxypropane,2,2-hexamethylene-1,3-dimethoxypropane,1,2-bis(methoxymethyl)cyclohexane, 2,8-dioxaspiro[5,5]undecane,3,7-dioxaspiro[3,3,1]nonane, 3,7-dioxabicyclo-[3,3,0]octane,3,3-diisobutyl-1,5-oxononane, 6,6-diisobutyldioxyheptane,1,1-dimethoxymethylcyclopentane, 1,1-bis(dimethoxymethyl)cyclohexane,1,1-bis(methoxymethyl)bicyclo[2,2,1]heptane,1,1-dimethoxymethylcyclo-pentane,2-methyl-2-methoxymethyl-1,3-dimethoxypropane,2-cyclohexyl-2-ethoxymethyl-1,3-diethoxypropane,2-cyclohexyl-2-methoxymethyl-1,3-dimethoxypropane,2,2-diisobutyl-1,3-dimethoxycyclohexane,2-isopropyl-2-isoamyl-1,3-dimethoxycyclohexane,2-cyclohexyl-2-methoxymethyl-1,3-dimethoxycyclohexane,2-isopropyl-2-methoxymethyl-1,3-dimethoxycyclo-hexane,2-isobutyl-2-methoxymethyl-1,3-dimethoxycyclohexane,2-cyclohexyl-2-ethoxymethyl-1,3-diethoxycyclohexane,2-cyclohexyl-2-ethoxymethyl-1,3-dimethoxycyclohexane,2-isopropyl-2-ethoxymethyl-1,3-diethoxycyclohexane,2-isopropyl-2-ethoxymethyl-1,3-dimethoxycyclo-hexane,2-isobutyl-2-ethoxymethyl-1,3-diethoxycyclohexane,2-isobutyl-2-ethoxymethyl-1,3-dimethoxycyclohexane,tris(p-methoxyphenyl)phosphine, methylphenylbis(methoxymethyl)silane,diphenylbis(methoxymethyl)-silane,methylcyclohexylbis(methoxymethyl)silane,di-t-butylbis(methoxy-methyl)silane,cyclohexyl-t-butylbis(methoxymethyl)silane andi-propyl-t-butylbis(methoxymethyl)silane.

Among these compounds, 1,3-diethers are preferable and2,2-diisobutyl-1,3-dimethoxypropane,2-isopropyl-2-isopentyl-1,3-dimethoxy-propane,2,2-dicyclohexyl-1,3-dimethoxypropane,2,2-bis(cyclohexyl-methyl)-1,3-dimethoxypropane,2-cyclohexyl-2-isopropyl-1,3-dimethoxy-propane,2-isopropyl-2-s-butyl-1,3-dimethoxypropane,2,2-diphenyl-1,3-dimethoxypropane and2-cyclopentyl-2-isopropyl-1,3-dimethoxypropane are more preferable.

The above compounds may be used singly or in combination of two or more.

(e) Silicon Compound

In the present invention, a silicon compound represented by thefollowing general formula (IV):Si(OR¹⁶)_(q)X² _(4-q)  (IV)may be used as component (e) in combination with components (a), (b) and(d) described above in the preparation of the solid catalyst component,where necessary. In the above general formula (IV), R¹⁶ represents ahydrocarbon group, X² represents a halogen atom and q represents aninteger of 0 to 3. By using the silicon compound, the catalyst activityand the stereoregularity can be improved and the amount of fine powderin the formed polymer can be decreased.

In the above general formula (IV), X² represents a halogen atom.Chlorine atom and bromine atom are preferable as the halogen atom. R¹⁶represents a hydrocarbon group which may be a saturated group or anunsaturated group, may be a linear group, a branched group or a cyclicgroup and may have heteroatoms such as sulfur atom, nitrogen atom,oxygen atom, silicon atom and phosphorus atom. It is preferable that theabove hydrocarbon group is a hydrocarbon group having 1 to 10 carbonatoms and more preferably an alkyl group, an alkenyl group, acycloalkenyl group, an aryl group or an aralkyl group. When a pluralityof the group represented by —OR¹⁶ are present, the plurality of groupsmay be the same with or different from each other. Examples of the grouprepresented by R¹⁶ include methyl group, ethyl group, n-propyl group,isopropyl group, n-butyl group, sec-butyl group, isobutyl group,n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-decylgroup, allyl group, butenyl group, cyclopentyl group, cyclohexyl group,cyclohexenyl group, phenyl group, tolyl group, benzyl group and phenetylgroup. q represents an integer of 0 to 3.

Examples of the silicon compound represented by the above generalformula (IV) include silicon tetrachloride, methoxytrichlorosilane,dimethoxydichlorosilane, trimethoxychlorosilane, ethoxytrichlorosilane,diethoxydichlorosilane, triethoxychlorosilane, propoxytrichlorosilane,dipropoxydichlorosilane and tripropoxychlorosilane. Among thesecompounds, silicon tetrachloride is preferable. The silicon compound maybe used singly or in combination of two or more.

(Preparation of the Solid Catalyst Component)

To prepare (A) the solid catalyst component in the first invention, (a)the magnesium compound, (b) the titanium compound and, where necessary,(d) the electron-donating agent and (e) the silicon compound are broughtinto contact with each other in accordance with a conventional process.

Examples of the conventional process include processes described inJapanese Patent Application Laid-Open Nos. Showa 53(1978)-43094, Showa55(1980)-135102, Showa 55(1980)-135103 and Showa 56(1981)-18606.Specific examples include the following processes. (1) The magnesiumcompound or a complex compound prepared from the magnesium compound andthe electron-donating agent is pulverized in the presence of theelectron-donating agent and, where desired, an auxiliary pulverizingagent and the resultant product is reacted with the titanium compound.(2) A liquid material of the magnesium compound having no reducingability and the titanium compound in the liquid state are reacted witheach other in the presence of the electron-donating agent and a solidtitanium complex compound is precipitated. (3) The product obtained in(1) or (2) described above is reacted with the titanium compound. (4)The product obtained in (1) or (2) described above is reacted with theelectron-donating agent and the titanium compound. (5) The magnesiumcompound or a complex compound prepared from the magnesium compound andthe electron-donating agent is pulverized in the presence of theelectron-donating agent, the titanium compound and, where desired, anauxiliary pulverizing agent and the product is treated with a halogen ora halogen compound.

Further examples of the process for preparing the solid catalystcomponent of component (A) include processes described in JapanesePatent Application Laid-Open Nos. Showa 56(1981)-166205, Showa57(1982)-63309, Showa 57(1982)-190004, Showa 57(1982)-300407 and Showa58(1982)-47003. The solid catalyst component of component (A) can alsobe prepared by bringing a solid substance, which contains magnesiumsupported on an oxide of an element belonging to any of Groups II to IVof the Periodic Table such as silicon oxide and magnesium oxide or on acomplex oxide containing at least one of oxides of elements belonging toany of the Groups II to IV of the Periodic Table such as silica alumina,into contact with the electron-donating agent and the titanium compoundin a solvent at a temperature in the range of 0 to 200° C. andpreferably in the range of 10 to 150° C. for a time in the range of 2minutes to 24 hours.

The amount of the titanium compound is, in general, in the range of 0.5to 100 mole and preferably in the range of 1 to 50 mole per 1 mole ofmagnesium in the above magnesium compound. The amount of theelectron-donating agent is, in general, in the range of 0.01 to 10 moleand preferably in the range of 0.05 to 1.0 mole per 1 mole of magnesiumin the above magnesium compound. Silicon tetrachloride may further beadded as the halide.

The temperature of bringing the components into contact with each otheris, in general, in the range of −20 to 200° C. and preferably in therange of 20 to 150° C. The time of contact is, in general, in the rangeof 1 minute to 24 hours and preferably in the range of 10 minutes to 6hours. The method for bringing the components into contact with eachother is not particularly limited. The components may be brought intocontact with each other, for example, in the presence of an inertsolvent such as a hydrocarbon or after diluting the components with aninert solvent such as a hydrocarbon. Examples of the inert solventinclude aliphatic hydrocarbons such as n-pentane, isopentane, n-hexane,n-heptane, n-octane and isooctane; aromatic hydrocarbons such asbenzene, toluene and xylene; and mixtures of these solvents.

It is preferable that the titanium compound is brought into contact withthe other components twice or more so that the titanium compound issufficiently supported on the magnesium compound which plays the role ofthe catalyst support. The solid catalyst component obtained after thecontact may be washed with an inert solvent such as a hydrocarbon.Examples of the inert solvent include the inert solvents describedabove. The obtained solid product can be kept under a dry condition orin an inert solvent such as a hydrocarbon.

In the second invention, any solid catalyst component comprising (b) thetitanium compound and (d) the electron-donating agent can be used as thesolid catalyst component of component (A). It is preferable that a solidcatalyst component is obtained by bringing (b) the titanium compound and(a) the magnesium compound into contact with each other in the presenceof (d) the electron-donating agent at a temperature of 120 to 150° C.,followed by washing the product with an inert solvent at a temperatureof 100 to 150° C. It is more preferable that the above treatments areconducted in the presence of (e) the silicon compound in combinationwith (d) the electron-donating agent. The method for bringing thecomponents into contact with each other is not particularly limited. Forexample, the components may be brought into contact with each other inthe presence of an inert solvent such as a hydrocarbon or after dilutingthe components with an inert solvent such as a hydrocarbon in advance.Examples of the inert solvent include aliphatic hydrocarbons such asn-octane, n-decane and ethylcyclohexane; alicyclic hydrocarbons; andmixtures of these solvents.

The titanium compound is used in an amount, in general, in the range of0.5 to 100 mole and preferably in the range of 1 to 50 mole per 1 moleof magnesium in the magnesium compound. When the ratio of the amounts bymole is outside the above range, the catalyst activity is occasionallyinsufficient. The electron-donating agent is used in an amount, ingeneral, in the range of 0.01 to 10 mole and preferably in the range of0.05 to 1.0 mole per 1 mole of magnesium in the magnesium compound. Whenthe ratio of the amounts by mole is outside the above range, thecatalyst activity and the stereoregularity are occasionallyinsufficient.

The above components are brought into each other at a temperature in therange of 120 to 150° C. and preferably in the range of 125 to 140° C.after the entire components are mixed together. When the temperature isoutside the above range, the effect of improving the catalyst activityand the stereoregularity is not sufficiently exhibited, occasionally.The above components are brought into contact with each other for atime, in general, in the range of 1 minute to 24 hours and preferably inthe range of 10 minutes to 6 hours. When a solvent is used, the range inthe pressure is various depending on the solvent and the temperature ofthe contact. The pressure is, in general, in the range of 0 to 5 MPaGand preferably in the range of 0 to 1 MPaG. From the standpoint of theuniformity and the efficiency of the contact, it is preferable that themixture is stirred when the components are brought into contact witheach other.

It is preferable that the titanium compound is brought into contact withthe other components twice or more so that the titanium compound issufficiently supported on the magnesium compound which plays the role ofthe catalyst support.

When a solvent is used in the operation of bringing the components intocontact with each other, the solvent is used in an amount, in general,in the range of 5,000 ml or less and preferably in the range of 10 to1,000 ml per 1 mole of the titanium compound. When the amount of thesolvent is outside the above range, the uniformity of the catalyst andthe efficiency of the contact occasionally deteriorate.

It is preferable that the solid catalyst component obtained after thecomponents are brought into contact with each other as described aboveis washed with an inert solvent at a temperature in the range of 100 to150° C. and preferably in the range of 120 to 140° C. When thetemperature of washing is outside the above range, the effect ofimproving the catalyst activity and the stereoregularity is notsufficiently exhibited, occasionally. Examples of the inert solventinclude aliphatic hydrocarbons such as n-octane and n-decane; alicyclichydrocarbons such as methylcyclohexane and ethylcyclohexane; aromatichydrocarbons such as toluene and xylene; halogenated hydrocarbons suchas tetrachloroethane and chlorofluoro-carbons; and mixtures of thesesolvents. Among these solvents, aliphatic hydrocarbons are preferable.

The process of washing is not particularly limited. Decantation andfiltration are preferable. The amount of the inert solvent, the time ofthe washing and the number of repeated washing are not particularlylimited. In general, the solvent is used in an amount in the range of100 to 100,000 ml and preferably in the range of 1,000 to 50,000 ml per1 mole of the magnesium compound and the washing is conducted, ingeneral, for a time in the range of 1 minute to 24 hours and preferablyin the range of 10 minutes to 6 hours. When the conditions are outsidethe above ranges, the washing is occasionally insufficient.

The range of the pressure in the washing is various depending on thesolvent and the temperature of the washing. The pressure is, in general,in the range of 0 to 5 MPaG and preferably in the range of 0 to 1 MPaG.It is preferable that the mixture containing the solid catalystcomponent is stirred during the washing of the solid catalyst componentfrom the standpoint of the uniformity and the efficiency of the washing.

The obtained solid catalyst component can be kept under a dry conditionor in an inert solvent such as a hydrocarbon.

(B) Organoaluminum Compound

The organoaluminum compound of component (B) used as the essentialcomponent in the first and second inventions is not particularlylimited. For example, an aluminum compound having an alkyl grouprepresented by the following general formula (VIII):R²⁹ _(m)Al(OR³⁰)_(n)X³ _(3-n-m)  (VIII)can be preferably used. In the above general formula, R²⁹ and R³⁰ eachrepresent an alkyl group having 1 to 8 carbon atoms and preferably 1 to4 carbon atoms, X³ represents a halogen atom, m represents a number inthe range of 0<m≦3, preferably 2 or 3 and most preferably 3 and nrepresents a number in the range of 0≦n<3 and preferably 0 or 1.

Examples of the organoaluminum compound include trialkylaluminums suchas trimethylaluminum, triethylaluminum, triisopropylaluminum,triisobutylaluminum and trioctylaluminum; dialkylaluminum monohalidessuch as diethylaluminum monochloride, diisopropylaluminum monochloride,diisobutylaluminum monochloride and dioctylaluminum monochloride; andalkylaluminum sesquihalides such as ethylaluminum sesquichloride. Amongthe above organo-aluminum compounds, trialkylaluminums having a loweralkyl group having 1 to 5 carbon atoms are preferable andtrimethylaluminum, triethylaluminum, tripropylaluminum andtriisobutylaluminum are more preferable. The organoaluminum compound maybe used singly or in combination of two or more.

In the first invention, the content of hydroaluminum compounds in (B)the organoaluminum compound is 0.1% by weight or smaller and preferably0.01% by weight or smaller. When the content of the hydroaluminumcompounds exceeds 0.1% by weight, α-olefin polymers exhibiting excellentfluidity and having a decreased amount of catalyst residues in thepolymer cannot be produced industrially advantageously.

(C) Organozinc Compound

As component (C) which is the essential component in the first andsecond inventions, an organozinc compound represented by the generalformula:ZnR¹R²is preferable. In the general formula, R¹ and R² each represent ahydrocarbon group having 1 to 10 carbon atoms and may represent the samegroup or different groups, Examples of the hydrocarbon group having 1 to10 carbon atoms include methyl group, ethyl group, various types ofpropyl groups, various types of butyl groups, various types of hexylgroups and various types of octyl groups. Examples of the alkylzinccompound include dimethylzinc, diethylzinc, di-n-propylzinc,diispropylzinc and di-n-butylzinc and diisobutylzinc. Among thesealkylzinc compounds, dimethylzinc and diethylzinc are preferable.(D) Electron-Donating Compound

As the electron-donating compound which is added, where necessary,during the polymerization in the first and second invention,organosilicon compounds having the Si—O—C bond, compounds havingnitrogen, compounds having phosphorus and compounds having oxygen can beused. From the standpoint of the polymerization activity and thestereoregularity, it is preferable that the organosilicon compoundshaving the Si—O—C bond are used among the above compounds.

Examples of the organosilicon compounds having the Si—O—C bond includetetramethoxysilane, tetraethoxysilane, tetrabutoxysilane,tetraisobutoxysilane, trimethylmethoxysilane, trimethylethoxysilane,triethylmethoxysilane, triethylethoxysilane,ethylisopropyldimethoxy-silane, propylisopropyldimethoxysilane,diisopropyldimethoxysilane, diisobutyldimethoxysilane,isopropylisobutyldimethoxysilane, di-t-butyldimethoxysilane,t-butylmethyldimethoxysilane, t-butylethyl-dimethoxysilane,t-butylpropyldimethoxysilane, t-butylisopropyl-dimethoxysilane,t-butylbutyldimethoxysilane, t-butylisobutyldimethoxy-silane,t-butyl(s-butyl)dimethoxysilane, t-butylamyldimethoxysilane,t-butylhexyldimethoxysilane, t-butylheptyldimethoxysilane,t-butyloctyl-dimethoxysilane, t-butylnonyldimethoxysilane,t-butyldecyldimethoxy-silane,t-butyl(3,3,3-trifluoromethylpropyl)dimethoxysilane,cyclohexyl-methyldimethoxysilane, cyclohexylethyldimethoxysilane,cyclohexyl-propyldimethoxysilane, cyclopentyl-t-butyldimethoxysilane,cyclohexyl-t-butyldimethoxysilane, dicyclopentyldimethoxysilane,dicyclohexyl-dimethoxysilane, bis(2-methylcyclopentyl)dimethoxysilane,bis(2,3-dimethylcyclopentyl)dimethoxysilane, diphenyldimethoxysilane,phenyl-triethoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane,propyl-trimethoxysilane, isopropyltrimethoxysilane,butyltrimethoxysilane, isobutyltrimethoxysilane,t-butyltrimethoxysilane, s-butyltrimethoxy-silane, amyltrimethoxysilane,isoamyltrimethoxysilane, cyclopentyl-trimethoxysilane,cyclohexyltrimethoxysilane, norbornanetrimethoxy-silane,indenyltrimethoxysilane, 2-methylcyclopentyltrimethoxysilane,cyclopentyl(t-butoxy)dimethoxysilane,isopropyl(t-butoxy)dimethoxysilane, t-butyl(isobutoxy)dimethoxysilane,t-butyl(t-butoxy)dimethoxysilane, thexyltriemthoxysilane,thexylisopropoxydimethoxysilane, thexyl(t-butoxy)dimethoxysilane,thexylmethyldimethoxysilane, thexylethyl-dimethoxysilane,thexylisopropyldimethoxysilane, thexylcyclopentyl-dimethoxysilane,thexylmyristyldimethoxysilane and thexylcyclohexyl-dimethoxysilane.

The above organosilicon compound may be used singly or in combination oftwo or more.

Silicon compounds represented by the following general formula (V):

can also be used. In the above general formula, R¹⁸ to R²⁰ eachrepresent hydrogen atom or a hydrocarbon group and may represent thesame group or different groups, adjacent groups represented by any ofR¹⁸ to R²⁰ may be bonded to each other and form a ring, R²¹ and R²² eachrepresent a hydrocarbon group and may represent the same group ordifferent groups, adjacent groups represented by R²¹ and R²² may bebonded to each other and form a ring, R²³ and R²⁴ each represent analkyl group having 1 to 20 carbon atoms and may represent the same groupor different groups, m represents an integer of 2 or greater and nrepresents an integer of 2 or greater.

Examples of the atom and the group represented by R¹⁸ to R²⁰ in generalformula (V) include hydrogen atom; linear hydrocarbon groups such asmethyl group, ethyl group and n-propyl group; branched hydrocarbongroups such as isopropyl group, isobutyl group, t-butyl group and thexylgroup; saturated cyclic hydrocarbon groups such as cyclobutyl group,cyclopentyl group and cyclohexyl group; and unsaturated cyclichydrocarbon groups such as phenyl group and pentamethylphenyl group.Among these groups, hydrogen atom and linear hydrocarbon groups having 1to 6 carbon atoms are preferable and hydrogen atom, methyl group andethyl group are more preferable.

Examples of the group represented by R²¹ and R²² include linearhydrocarbon groups such as methyl group, ethyl group and n-propyl group;branched hydrocarbon groups such as isopropyl group, isobutyl group,t-butyl group and thexyl group; saturated cyclic hydrocarbon groups suchas cyclobutyl group, cyclopentyl group and cyclohexyl group; andunsaturated cyclic hydrocarbon groups such as phenyl group andpentamethylphenyl group. The groups represented by R²¹ and R²² may bethe same with or different from each other. Among these groups, hydrogenatom and linear hydrocarbon groups having 1 to 6 carbon atoms arepreferable and hydrogen atom, methyl group and ethyl group are morepreferable.

Examples of the group represented by R²³ and R²⁴ include linear orbranched alkyl groups such as methyl group, ethyl group, n-propyl group,isopropyl group, n-butyl group, isobutyl group, sec-butyl group, t-butylgroup, n-pentyl group, n-hexyl group and n-octyl group. The groupsrepresented by R²³ and R²⁴ may be the same with or different from eachother. Among these groups, linear hydrocarbon groups having 1 to 6carbon atoms are preferable and methyl group is more preferable.

Examples of the silicon compound represented by general formula (V)include neopentyl-n-propyldimethoxysilane,neopentyl-n-butyldimethoxysilane, neopentyl-n-pentyldimethoxysilane,neopentyl-n-hexyldimethoxysilane, neopentyl-n-hexyldimethoxysilane,isobutyl-n-propyldimethoxysilane, isobutyl-n-butyldimethoxysilane,isobutyl-n-pentyldimethoxysilane, isobutyl-n-hexydimethoxysilane,isobutyl-n-heptyldimethoxysilane,2-cyclohexylpropyl-n-propyldimethoxysilane,2-cyclohexylbutyl-n-propyldimethoxysilane,2-cyclohexylpentyl-n-propyl-dimethoxysilane,2-cyclohexylhexyl-n-propyldimethoxysilane,2-cyclohexylheptyl-n-propyldimethoxysilane,2-cyclopentylpropyl-n-propy-ldimethoxysilane,2-cyclopentylbutyl-n-propyldimethoxysilane,2-cyclopentylpentyl-n-propyldimethoxysilane,2-cyclopentylhexyl-n-propyl-dimethoxysilane,2-cyclopentylheptyl-n-propyldimethoxysilane,isopentyl-n-propyldimethoxysilane, isopentyl-n-butyldimethoxysilane,isopentyl-n-pentyldimethoxysilane, isopentyl-hexyldimethoxysilane,isopentyl-n-hexyldimethoxysilane, isopentyl-n-heptyldimethoxysilane,isopentyl-isobutyldimethoxysilane, isopentylneopentyldimethoxysilane,diisopentyl-dimethoxysilane, diisoheptyldimethoxysilane,diisohexyldimethoxysilane and dicyclopentyldimethoxysilane. Preferableexamples of the compound include neopentyl-n-propyldimethoxysilane,neopentyl-n-pentyl-dimethoxysilane, isopentylneopentyldimethoxysilane,diisopentyl-dimethoxysilane, diisoheptyldimethoxysilane,diisohexyldimethoxysilane and dicyclopentyldimethoxysilane. Morepreferable examples of the compound includeneopentyl-n-pentyldimethoxysilane, diisopentyl-dimethoxysilane anddicyclopentyldimethoxysilane.

The silicon compound represented by general formula (V) can besynthesized in accordance with any desired process. A typical route ofsynthesis is shown in the following:

In this route of synthesis, material compound [1] is commerciallyavailable or can be obtained in accordance with a conventional processof alkylation or halogenation. The organosilicon compound represented bygeneral formula (V) can be obtained in accordance with the known processof the Grignard reaction with compound [1].

The above organosilicon compound may be used singly or in combination oftwo or more.

Examples of the compound having nitrogen include 2,6-disubstitutedpiperidines such as 2,6-diisopropylpiperidine,2,6-diispropyl-4-methylpiperidine andN-methyl-2,2,6,6-tetramethylpiperidine; 2,5-disubstituted azolidinessuch as 2,5-diisopropylazolidine andN-methyl-2,2,5,5-tetramethylazolidine; substituted methylenediaminessuch as N,N,N′,N′-tetramethylmethylenediamine andN,N,N′,N′-tetraethyl-methylenediamine; and substituted imdazolidinessuch as 1,3-dibenzyl-imidazolidine and1,3-dibenzyl-2-phenylimidazolidine.

Examples of the compound having phosphorus include esters of phosphorousacid such as triethylphosphite, tri-n-propoylphosphite,triisopropylphosphite, tri-n-butylphosphite, triisobutylphosphite,diethyl-n-butylphosphite and diethylphenylphosphite.

Examples of the compound having oxygen include 2,6-disubstitutedtetrahydrofurans such as 2,2,6,6-tetramethyltetrahydrofuran and2,2,6,6-tetraethyltetrahydrofuran; dimethoxymethane derivatives such as1,1-dimethoxy-2,3,4,5-tetrachloropentadiene and 9,9-dimethoxyfluoreneand diphenyldimethoxymethane; and polyethers described in the above for(d) the electron-donating agent.

As the organosilicon compound used where necessary in the secondinvention, for example, organosilicon compounds of the electron-donatingcompound represented by the following general formula (VI):Si(OR²⁵)_(q)R²⁶ _(4-q)  (VI)can be used. In the above general formula (VI), R²⁵ and R²⁶ eachrepresent a hydrocarbon group and may represent the same group ordifferent groups and q represents an integer of 0 to 3.

In the above general formula (VI), R²⁵ and R²⁶ each represent ahydrocarbon group and may represent the same group or different groups,as described above. The hydrocarbon group may be a saturated group or anunsaturated group, may be a linear group, a branched group or a cyclicgroup and may have a hetero atom such as sulfur, nitrogen, oxygen,silicon and phosphorus. It is preferable that the hydrocarbon group is ahydrocarbon having 1 to 10 carbon atoms and more preferably an alkylgroup, an alkenyl group, a cycloalkenyl group, an aryl group or anaralkyl group. When a plurality of groups represented by —OR²⁵ arepresent, the plurality of groups may be the same with or different fromeach other. Examples of the group represented by R²⁵ and R²⁶ includemethyl group, ethyl group, n-propyl group, isopropyl group, n-butylgroup, sec-butyl group, isobutyl group, n-pentyl group, n-hexyl group,n-heptyl group, n-octyl group, n-decyl group, allyl group, butenylgroup, cyclopentyl group, cyclohexyl group, cyclohexenyl group, phenylgroup, tolyl group, benzyl group and phenetyl group. q represents aninteger of 0 to 3.

Examples of the organosilicon compound represented by general formula(VI) include the compounds described as the examples of theorganosilicon compound having Si—O—C bond.

(Process for Producing an α-Olefin Polymer)

The amount of the catalyst used in the first invention is notparticularly limited. In general, the solid catalyst component ofcomponent (A) is used in an amount such that the amount of the titaniumatom is in the range of 0.00005 to 1 mmole per 1 liter of the reactionvolume. The organoaluminum compound of component (B) is used in such anamount that the ratio of the amounts by atom of aluminum to titanium is,in general, in the range of 1 to 5,000 and preferably in the range of 10to 500. When the ratio of the amounts by atom is outside the aboverange, the catalyst activity is occasionally insufficient. When theelectron-donating compound such as the organosilicon compound ofcomponent (D) is used, the electron-donating compound is used in such anamount that the ratio of the amounts by mole of (D) theelectron-donating compound to (B) the organoaluminum compound is, ingeneral, in the range of 0.001 to 5.0, preferably in the range of 0.01to 2.0 and more preferably in the range of 0.05 to 1.0. When the ratioof the amounts by mole is outside the above range, sufficient catalystactivity and stereoregularity are not obtained, occasionally.

In the first invention, an α-olefin represented by general formula(VII):R²⁷—CH═CH₂  (VII)is used.

In the above general formula (VII), R²⁷ represents hydrogen atom or ahydrocarbon group which may be a saturated group or an unsaturatedgroup. Examples of the α-olefin include ethylene, propylene, 1-butene,1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 3-methyl-1-pentene,4-methyl-1-pentene, vinylcyclohexane, butadiene, isoprene andpiperylene. The α-olefin may be used singly or in combination of two ormore. Among the above α-olefins, ethylene and propylene are preferable.

In the first invention, the polymerization is conducted in the presenceof (A) the above solid catalyst component, (B) the above organoaluminumcompound, (C) the above organozinc compound and, where necessary, (D)the above electron-donating compound. The polymerization may beconducted in the gas phase or in the liquid phase. The polymerizationmay also be conducted by bringing the monomer component into contactwith the above catalyst components while the catalyst components aresuspended in a slurry in an inert solvent such as n-butane, n-pentane,isopentane, n-hexane, n-heptane, n-octane, cyclohexane, toluene andxylene or by bringing the monomer into contact with the catalystcomponents in the gas phase. The polymerization may also be conducted inthe liquid propylene.

The amount of (C) the organozinc compound is not particularly limited aslong as the effect of the present invention can be exhibited.

In the first invention, where desired, the olefin may be preliminarilypolymerized and the major polymerization is conducted thereafter so thatthe desired polymerization activity, stereoregularity and form of thepolymer powder can be obtained. When the preliminary polymerization isconducted, the olefin is preliminarily polymerized, in general, at atemperature of 100° C. or lower and preferably in the range of −10 to80° C. at a pressure in the range of the ordinary pressure to about 5MPaG in the presence of a catalyst prepared by mixing (A) the abovesolid catalyst component, (B) the above organoaluminum compound and,where necessary, (C) the above organozinc compound and/or (D) the aboveelectron-donating compound in specific relative amounts in an inertsolvent such as n-butane, n-pentane, isopentane, n-hexane, n-heptane,n-octane, cyclohexane, toluene and xylene and a product of preliminarypolymerization (hereinafter, referred to as a preliminary polymerizedcatalyst, occasionally) is obtained. Hydrogen may be present or absentin the preliminary polymerization. It is preferable that the amount ofthe preliminarily polymerized olefin is 0.01 to 5,000 g and morepreferably 0.05 to 1,000 g per 1 g of (A) the above solid catalystcomponent.

Examples of the olefin used for the preliminary polymerization includeolefins described as the examples of the α-olefin represented by generalformula (VII). The olefin may be used singly or in combination of two ormore. Among the above olefins, ethylene and propylene are preferable.

When the preliminary polymerization is conducted, the componentsdescribed above are mixed together. The preliminary polymerization maybe conducted by introducing the olefin directly after mixing thecomponents or after mixing the components and aging the resultantmixture for 0.2 to 3 hours.

It is preferable that the major polymerization of the olefin isconducted in the presence of the preliminarily polymerized catalyst,component (B), component (C) and component (D) since the polymerizationactivity and the stereoregularity are improved and an olefin polymerexhibiting excellent fluidity can be obtained. The amounts of thepreliminary polymerized catalyst obtained as described above, component(B), component (C) and component (D) used in the major polymerizationare as follows. The preliminarily polymerized catalyst is used in anamount such that the amount of titanium atom in the preliminarilypolymerized catalyst is, in general, in the range of 0.00005 to 1 mmoleper 1 liter of the volume of the reaction mixture. The organoaluminumcompound of component (B) is used in an amount such that the ratio ofthe amounts by atom of aluminum to titanium is, in general, in the rangeof 1 to 5,000 and preferably in the range of 1 to 300. When theelectron-donating compound such as the organosilicon compound is used ascomponent (D), the electron-donating compound is used in an amount suchthat the ratio of the amounts by mole of (D) the electron-donatingcompound to (B) the organoaluminum compound is, in general, in the rangeof 0.001 to 5.0 and preferably in the range of 0.01 to 2.0. When theratio of the amounts by mole is outside the above range, sufficientcatalyst activity and stereoregularity are not obtained, occasionally.

Component (C) is used in an amount such that the ratio of the amounts byatom of zinc to titanium is, in general, in the range of 1 to 1,000 andpreferably 10 to 500. When the ratio of the amounts by atom is outsidethe above range, the catalyst activity is occasionally insufficient.

The form of the major polymerization is not particularly limited and anyof the solution polymerization, the slurry polymerization, the gas phasepolymerization and the bulk polymerization may be conducted. Any of thebatch polymerization and the continuous polymerization may be conducted.The polymerization may also be conducted in accordance with a two-stagepolymerization or a multi-stage polymerization under conditionsdifferent between the stages.

The reaction conditions are as follows. The pressure of thepolymerization is not particularly limited. The pressure is suitablyselected, in general, in the range of the atmospheric pressure to 8 MPaGand preferably in the range of 0.2 to 5 MPaG from the standpoint of thepolymerization activity. The temperature is suitably selected, ingeneral, in the range of 0 to 200° C., preferably in the range of 20 to150° C. and more preferably in the range of 40 to 100° C. The time ofpolymerization cannot be generally decided since the time is variousdepending on the temperature of polymerization of the olefin used as thematerial. The time of polymerization is, in general, in the range of 5minutes to 20 hours and preferably in the range of 10 minutes to 10hours.

The molecular weight can be adjusted by adding a chain transfer agentsuch as hydrogen gas. An inert gas such as nitrogen gas may be present.

In the first invention, the polymerization can be conducted by using thecomponents in various orders. For example, component (A), component (B)and component (D) are mixed in specific relative amounts and thecomponents are brought into contact with each other. The preliminarypolymerization may be conducted, where desired, and component (C) isbrought into contact with the above mixture or with the obtainedpreliminarily polymerized catalyst. Propylene is introduced directlyafter the addition of component (C) and the major polymerization isconducted. Alternatively, after component (A), component (B) andcomponent (D) are brought into contact with each other, the mixture isaged for 0.2 to 3 hours. The preliminary polymerization may beconducted, where desired, and component (C) is brought into contact withthe above mixture or with the preliminarily polymerized catalyst.Propylene is introduced after the addition of component (C) and themajor polymerization is conducted. The above catalyst components may besupplied after being suspended in an inert solvent or in the olefin usedas the raw material

In the first invention, the after-treatment of the polymerization can beconducted in accordance with a conventional process. In the gas phasepolymerization, the polymer powder released from the polymerizationreactor may be treated with nitrogen gas passing through the powder toremove the olefin and the like remaining in the powder or, wheredesired, may be pelletized by an extruder. A small amount of water or analcohol may be added during the above treatments so that the catalyst iscompletely inactivated. In the bulk polymerization, after thepolymerization is completed, the monomer is completely separated fromthe polymer released from the polymerization reactor and the polymer ispelletized.

Typical examples of the polymer of olefins obtained in accordance withthe first invention include polymers of propylene. The polymer ofpropylene may be a homopolymer of propylene or a copolymer of propylenewith ethylene and/or an α-olefin having 4 or more carbon atoms. Thecopolymer of propylene may be a random copolymer or a block copolymer.Examples of the homopolymer of propylene include homopolymers ofpropylene having extremely high stereoregularity such as a fraction ofthe (mmmm) pentad exceeding 95% by mole as measured in accordance with¹³C-NMR and exhibiting high fluidity such as a melt flow rate, ingeneral, in the range of 20 to 1,000 g/10 minutes and preferably in therange of 50 to 500 g/10 minutes as measured in accordance with themethod of ASTM D1238 under the condition of the temperature of 230° C.and the load of 21.18 N.

(Process for Producing a Block Copolymer of Propylene)

In the second invention, it is preferable that a preliminarilypolymerized catalyst is prepared and then the major polymerization isconducted from the standpoint of the polymerization activity, thestereoregularity and the form of powder of the polymer. Thepreliminarily polymerized catalyst can be prepared by bringing (A) theabove solid catalyst component, (B) the above organoaluminum and,preferably, (D) the above electron-donating compound into contact withan olefin such as propylene, ethylene, 1-butene and 1-hexene. The olefinmay be used singly or in combination of two or more. It is preferablethat the preliminary polymerization is conducted in an inert solventsuch as n-butane, n-pentane, isopentane, n-hexane, n-heptane, n-octane,cyclohexane, toluene and xylene. It is preferable that the preliminarypolymerization is conducted at a temperature, in general, in the rangeof 80° C. or lower, preferably in the range of −10 to 60° C. and morepreferably in the range of 0 to 50° C. at a pressure in the range of theatmospheric pressure to about 5 MPaG. The amount of the preliminarilypolymerized olefin is preferably 0.05 to 50 g and more preferably 0.1 to10 g per 1 g of (A) the above solid catalyst component.

When the preliminary polymerization is conducted, component (A),component (B) and component (D) may be mixed in specific relativeamounts and brought into contact with each other. The preliminarypolymerization may be conducted by introducing the olefin directly aftermixing component (A), component (B) and component (D) or after mixingcomponent (A), component (B) and component (D) and aging the resultantmixture for 0.2 to 3 hours.

In the first stage, propylene is homopolymerized in the presence of thepreliminarily polymerized catalyst obtained above, (B) theorganoaluminum compound, (C) the organozinc compound and, preferably,(D) the electron-donating compound. In the second stage, a comonomercomponent is introduced so that the copolymerization of propylene withthe comonomer takes place. Block PP can be obtained in this manner. Inthe homopolymerization of the first stage, a homopolymer of propyleneexhibiting fluidity such as a melt flow rate in the range of 20 to 1,000g/10 minutes and preferably in the range of 50 to 500 g/10 minutes asmeasured in accordance with the method of ASTM D1238 at the temperatureof 230° C. under the load of 21.2 N (2.16 kgf) can be obtained.

The comonomer is at least one of ethylene and α-olefins having 4 or morecarbon atoms. Examples of the α-olefin having 4 or more carbon atomsinclude 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene,3-methyl-1-pentene, 4-methyl-1-pentene, 1-dodecene, 1-tetradecene,1-hexadecene, 1-octadecene and 1-eicosene. The α-olefin may be usedsingly or in combination of two or more.

In the second invention, it is preferable that the homopolymer portion(the homopolymer of propylene) has an intrinsic viscosity in the rangeof 0.5 to 1.5 dl/g and more preferably in the range of 0.5 to 1.2 dl/gas measured in decalin at 135° C. so that sufficient fluidity can beobtained. It is preferable that the copolymer portion has an intrinsicviscosity in the range of 1.0 to 10 dl/g and more preferably in therange of 1.5 to 10 dl/g so that sufficient impact strength ismaintained.

The homopolymerization of propylene may be conducted in separate severalstages in accordance with the object. When the condition is changed inthe copolymerization, degassing is conducted where necessary and therelative amounts of the components and the amount of hydrogen can bechanged. It is preferable that (E) an electron-donating substance isadded in the production of block PP since a decrease in the molecularweight by addition of the organozinc compound can be substantiallyprevented by adding the electron-donating substance before or during thecopolymerization with the comonomer. As (E) the electron-donatingsubstance, the compounds described as the examples of (b) theelectron-donating agent and (D) the electron-donating compound can beused. Among these compounds, alcohols are preferable and ethanol is morepreferable. In this case, it is preferable that the amount of (E) theelectron-donating substance is in the range of about 0.01 to 1.5 moleper 1 mole of the total of (B) the organoaluminum compound and (C) theorganozinc compound which are used in the homopolymerization ofpropylene. When the amount of the electron-donating substance exceeds1.5 mole, the activity of the catalyst exceedingly decreases,occasionally.

The polymerization can be conducted in the gas phase or in the liquidphase. The polymerization may also be conducted by bringing the monomercomponent into contact with the preliminarily polymerized catalyst whilethe catalyst is suspended as a slurry in an inert solvent such asn-butane, n-pentane, isopentane, n-hexane, n-heptane, n-octane,cyclohexane, toluene and xylene or by bringing the monomer into contactwith the catalyst in the gas phase. The polymerization may also beconducted in the liquid propylene. Any of the batch polymerization andthe continuous polymerization may be conducted. The polymerization mayalso be conducted in accordance with a two-stage polymerization or amulti-stage polymerization under conditions different between thestages.

The amounts of the catalyst components used in the second invention arenot particularly limited. The solid catalyst component of component (A)is used in an amount such that the amount of titanium atom is, ingeneral, 0.00005 to 1 mmole per 1 liter of the volume of the reactionmixture. The organoaluminum compound of component (B) is used in anamount such that the ratio of the amounts by atom of aluminum totitanium is, in general, in the range of 1 to 1,000 and preferably inthe range of 10 to 500. When the ratio of the amounts is outside theabove range, the catalyst activity becomes occasionally insufficient.The organozinc compound of component (C) is used in an amount such thatthe ratio of the amounts by atom of aluminum to zinc is, in general, inthe range of 1 to 10,000, preferably in the range of 1 to 1,000 and morepreferably in the range of 1 to 500. When the ratio of the amounts byatom is smaller than 1, the effect of component (C) is not exhibited,occasionally. When the ratio of the amounts by atom exceeds 10,000, thecatalyst activity is occasionally insufficient. (D) Theelectron-donating compound is used in an amount such that the ratio ofthe amounts by mole of (D) the electron-donating compound to (B) theorganoaluminum compound is, in general, in the range of 0.001 to 5.0,preferably in the range of 0.01 to 2.0 and more preferably in the rangeof 0.05 to 1.0. When the ratio of the amounts by mole is outside theabove range, sufficient catalyst activity and stereoregularity are notobtained, occasionally. However, the ratio of the amounts by mole ofcomponent (D) to component (B) can be further decreased when thepreliminary polymerization is conducted.

The reaction conditions are as follows. The pressure is not particularlylimited. From the standpoint of the polymerization activity, thepressure is suitably selected, in general, in the range of theatmospheric pressure to 10 MPaG and the polymerization temperature issuitably selected, in general, in the range of −80 to 180° C. andpreferably in the range of 20 to 150° C.

In the second invention, the after-treatment of the polymerization canbe conducted in accordance with a conventional process. In the gas phasepolymerization, the polymer powder released from the polymerizationreactor may be treated with nitrogen gas passing through the powder toremove the olefin and the like remaining in the powder or, wheredesired, may be pelletized by an extruder. A small amount of water or analcohol may be added during the above treatments so that the catalyst iscompletely inactivated. In the bulk polymerization, after thepolymerization is completed, the monomer is completely separated fromthe polymer released from the polymerization reactor and the polymer ispelletized.

EXAMPLES

The present invention will be described more specifically with referenceto examples in the following. However, the present invention is notlimited to the examples.

In Examples 1 to 6 and Comparative Examples 1 to 3 which are examples ofthe first invention, the physical properties and the analytical valueswere obtained in accordance with the following methods.

(1) Intrinsic viscosity (η): A polymer was dissolved into decalin andthe intrinsic viscosity was measured at 135° C.

(2) Melt flow rate (MFR): The melt flow rate was measured in accordancewith the method of ASTM D1238 at 230° C. under a load of 21.18 N.

(3) Stereoregularity (the fraction of the (mmmm) pentad): A polymer wasdissolved in a mixed solvent containing 1,2,4-trichlorobenzene and heavybenzene in a ratio of the amounts by volume of 90:10. The signal ofmethyl group was obtained in accordance with the method of completedecoupling of proton at 130° C. using a ¹³C-NMR apparatus (manufacturedby NIPPON DENSHI Co., Ltd.; LA-500) and the fraction of the (mmmm)pentad was obtained from the obtained value. The fraction of theisotactic (mmmm) pentad used in the present invention means the fractionof the isotactic pentad in the pentad units in the molecular chain ofpolypropylene obtained from the ¹³C nuclear magnetic resonance spectrum,which was proposed by A. Zambelli et al. in “Macromolecules, 6, 925(1973)”. For the assignment of the peaks in the obtained ¹³C nuclearmagnetic resonance spectrum, the assignment proposed by A. Zambelli etal. in “Macromolecules, 8, 687 (1975)” was used.

(4) Content of aluminum hydride in an organoaluminum compound: Anorganoaluminum compound was hydrolyzed and the formed gas was analyzedin accordance with the gas chromatography.

In the examples of the first invention, the following threeorganoaluminum compounds were used.

Triethylaluminum A: the content of aluminum hydride was 0.6% by weight.Triethylaluminum B: the content of aluminum hydride was 0.05% by weight.Triethylaluminum C: the content of aluminum hydride was 0.004% byweight.

The content of aluminum hydride was adjusted by distilling commercialtriethylaluminum and, where necessary, mixing triethylaluminum obtainedafter the distillation with that before the distillation.

In Examples 7 to 11 and Comparative Examples 4 and 5 which are examplesof the second invention, the intrinsic viscosity [η], the content of thefraction soluble in p-xylene and the content of ethylene in the fractionsoluble in p-xylene were obtained in accordance with the followingmethods.

(1) Intrinsic viscosity [η]: A homopolymer portion or a fraction solublein p-xylene was dissolved in decalin and the intrinsic viscosity wasmeasured at 135° C.

(2) The content of the fraction soluble in p-xylene: The amount of thefraction soluble in p-xylene at 25° C. was obtained in accordance withthe following method.

A sample of a block copolymer of propylene and ethylene in an amount of5±0.05 g was accurately weighed and placed into a 1,000 mleggplant-shape flask. After 1±0.05 g of BHT (an antioxidant) was addedinto the flask, a stirrer and 700±10 ml of p-xylene were placed into theflask and a condenser was attached to the eggplant-shape flask. Theflask was heated for 120±30 minutes in an oil bath at 140±5° C. whilethe stirrer was rotated and the sample was dissolved in p-xylene. Thecontent of the flask was poured into a 1,000 ml beaker and cooled understirring by the stirrer while the beaker was left standing. After thecontent of the beaker was stirred until the temperature reached the roomtemperature (25° C.) (8 hours or longer), the precipitates were removedwith a metal net. The filtrate was filtered again with a filter paperand poured into 2,000 ml of methanol placed in a 3,000 ml beaker. Theobtained liquid was left standing under stirring by a stirrer for 2hours or longer. The precipitates were separated with a metal net, driedin the air for 5 hours or longer and then dried in a vacuum drier at100±5° C. for 240 to 270 minutes and the fraction soluble in p-xylenewas recovered.

When the amount by weight of the sample is expressed by A g and theamount of the recovered fraction soluble in p-xylene is expressed by Cg, the content of the fraction soluble in p-xylene in the sample iscalculated as: W (% by weight)=100×C/A.

(3) Content of ethylene unit in the fraction soluble in p-xylene: Thecontent of the ethylene unit in the fraction soluble in p-xylene wasmeasured in accordance with ¹³C-NMR as follows:

The fraction soluble in p-xylene was examined in accordance with ¹³C-NMRand the intensities by area of I(Tδδ), I(Tβδ), I(Sγδ), I(Sδδ), I(Tββ),I(Sβδ) and I(Sββ) of the peaks assigned to carbons of Tδδ, Tβδ, Sγδ,Sδδ, Tββ, Sβδ and Sββ, respectively, were obtained. Using the obtainedintensities by area, fractions of f_(EEE), f_(EPE), f_(PPE), f_(PPP),f_(PEE) and f_(PEP) of the triads EEE, EPE, PPE, PPP, PEE and PEP,respectively, were calculated in accordance with the followingequations:f _(EEE) =[I(Sδδ)/2+I(Sγδ)/4]/Tf _(EPE) =I(Tδδ)/Tf _(PPE) =I(Tβδ)/Tf _(PPP) =I(Tββ)/Tf _(PEE) =I(Sβδ)/Tf _(PEP) =I(Sββ)/Twherein T=I(Sδδ)/2+I(Sγδ)/4+I(Tδδ)+I(Tβδ)+I(Tββ)+I(Sβδ)+I(Sββ).

The content of the ethylene unit (% by mole) was calculated from thefractions obtained above in accordance with the following equation:Content  of  ethylene  unit  (%  by  mole) = 100{f_(EEE) + 2(f_(PEE) + f_(EPE))/3 + (f_(PEP) + f_(PEE))/3}

The content of the ethylene unit (% by weight) was calculated inaccordance with the following equation:Content  of  ethylene  unit  (%  by  weight) =   [28  E  t  (%  by  mole)/{28  Et  (%  by  mole) + 42(100 − E  t  (%  by  mole)}] × 100wherein the content of the ethylene unit (% by mole) is expressed byEt(% by mole).

For the measurement of ¹³C-NMR, the fraction soluble in p-xylene wasdissolved in a mixed solvent containing 1,2,4-trichlorobenzene and heavybenzene in a ratio of the amounts by volume of 90:10 and the measurementwas conducted in accordance with the method of complete decoupling ofproton at 130° C. using a ¹³C-NMR apparatus (manufactured by NIPPONDENSHI Co., Ltd.; LA-500).

Example 1

(1) Preparation of a Solid Catalyst Component

After a three-necked flask having an inner volume of 0.5 liters andequipped with a stirrer was purged with nitrogen, 60 ml of dehydratedn-octane and 16 g of diethoxymagnesium were placed into the flask. Theresultant mixture was heated at 40° C. and 2.4 ml of silicontetrachloride was added. After the resultant mixture was stirred for 20minutes, 1.6 ml of di-n-butyl phthalate was added. The obtained solutionwas heated at 80° C. and 77 ml of titanium tetrachloride was addeddropwise. The temperature inside the flask was raised to 125° C. and theoperation of contact was conducted under stirring for 2 hours. After thestirring was stopped, solid substances were precipitated and thesupernatant liquid was removed. Then, 100 ml of dehydrated n-octane wasadded. The resultant mixture was heated at 125° C. under stirring andkept at this condition for 1 minute. After the stirring was stopped,solid substances were precipitated and the supernatant liquid wasremoved. This operation of washing was repeated 7 times. Then, 122 ml oftitanium tetrachloride was added. The temperature inside the flask wasraised to 125° C. and the second operation of contact was conducted.Then, the operation of washing with dehydrated n-octane was repeated 6times and a solid catalyst component was obtained.

(2) Preparation of a Product of Preliminary Polymerization

After a three-necked flask having an inner volume of 0.5 liters andequipped with a stirrer was purged with nitrogen, a slurry in dehydratedn-octane containing the above solid catalyst component was added in anamount such that the mass of the solid substance was 12 g and thetemperature was kept at 25° C. After 1.5 g of triethylaluminum B wasadded and the resultant mixture was stirred for 15 minutes, 1.1 g ofdicyclopentyldimethoxysilane was added. The temperature of the resultantfluid was raised to 50° C. and propylene gas was introduced into thefluid at the rate of 50 ml/minute for 2 hours. Then, the introduction ofpropylene gas was stopped and the temperature was slowly lowered to 25°C. over 40 minutes. After the stirring was stopped, solid substanceswere precipitated and the supernatant liquid was removed. Then, 100 mlof dehydrated n-octane was added and the resultant fluid was stirred for1 minute. After the stirring was stopped, solid substances wereprecipitated and the supernatant liquid was removed. This operation ofwashing was repeated 5 times and a product of preliminary polymerizationwas obtained.

(3) Polymerization

Into an autoclave made of stainless steel, having an inner volume of 5liters and equipped with an inlet tube for materials and a stirrer, 30 gof homopolypropylene (the intrinsic viscosity: 0.96 dl/g) was placed asthe seed powder. After the inside of the autoclave was sufficientlydried under a reduced pressure, the temperature inside the autoclave wasraised to 80° C. under stirring. Hydrogen was introduced so that thepartial pressure of hydrogen was adjusted to 0.6 MPa. Then, propylenewas introduced and the total pressure was adjusted to 2.8 MPaG. Into theinlet tube for materials, 7.6 ml of triethylaluminum B (the content ofaluminum hydride: 0.05% by weight), 0.5 ml of diethylzinc and 20 ml ofdehydrated n-heptane were placed. These materials were then introducedinto the autoclave utilizing the difference in the pressure between theinlet tube and the autoclave. Into the inlet tube for materials, 20 mlof dehydrated n-heptane, 0.4 mmole of triethylaluminum B, 1.0 mmole ofdicyclopentyldimethoxysilane and the product of preliminarypolymerization in an amount such that the amount of titanium was 0.02mmole were placed. These materials were then introduced into theautoclave utilizing the difference in the pressure between the inlettube and the autoclave. The polymerization was allowed to proceed for 1hour while propylene was additionally introduced in a manner such thatthe total pressure was kept constant. Then, the temperature was loweredand the pressure was released. The product was taken out and dried undera reduced pressure and a polymer of propylene was obtained. The obtainedresults are shown in Table 1.

Example 2

The same procedures as those conducted in Example 1 were conductedexcept that diethylzinc was used in an amount of 1.0 mmole. The resultsare shown in Table 1.

Example 3

The same procedures as those conducted in Example 1 were conductedexcept that triethylaluminum C (the content of aluminum hydride: 0.004%by weight) was used. The results are shown in Table 1.

Example 4

The same procedures as those conducted in Example 3 were conductedexcept that diethylzinc was used in an amount of 1.0 mmole. The resultsare shown in Table 1.

Comparative Example 1

The same procedures as those conducted in Example 1 were conductedexcept that triethylaluminum A (the content of aluminum hydride: 0.6% byweight) was used. The results are shown in Table 1.

In Examples 1 and 3 and Comparative Example 1, the same amount ofdiethylzinc was used but the obtained MFR as the indicator of fluiditywas different. Sufficient fluidity was not obtained in ComparativeExample 1 in contrast to the fluidity obtained in Examples 1 and 3. Asshown in the result of Comparative Example 2, fluidity of the samedegree as those in Examples 1 and 3 could be obtained when the amount ofdiethylzinc was increased to twice the amount of Comparative Example 1.However, the amount of zinc residues contained in the polymer wasconsidered to be greater than those in the polymers of Examples 1 and 3when the yield was taken into consideration. Thus, it is shown that theprocesses in Examples 1 and 3 were more excellent from the standpoint ofachieving both of the decrease in the zinc residues in the polymer andthe excellent fluidity.

Comparative Example 2

The same procedures as those conducted in Comparative Example 1 wereconducted except that diethylzinc was used in an amount of 1.0 mmole.The results are shown in Table 1.

In Examples 2 and 4 and Comparative Example 2, the same amount ofdiethylzinc was used but the obtained MFR as the indicator of fluiditywas different. Sufficient fluidity was not obtained in ComparativeExample 2 in contrast to the fluidity obtained in Examples 1 and 3.

Example 5

An autoclave made of stainless steel, having an inner volume of 1 literand equipped with an inlet tube for materials and a stirrer wassufficiently dried and 360 ml of n-heptane, 2 mmole of triethylaluminumB, 1 mmole of diethylzinc and 0.25 mmole of dicyclopentyldimethoxysilanewere placed into the autoclave. The temperature was raised to 80° C. andhydrogen was introduced so that the partial pressure of hydrogen wasadjusted to 0.2 MPa. Then, propylene was introduced and the totalpressure was adjusted to 0.8 MPaG. Into the inlet tube for materials, 20ml of dehydrated n-heptane and the product of preliminary polymerizationin an amount such that the amount of titanium was 0.02 mmole wereplaced. These materials were then introduced into the autoclaveutilizing the difference in the pressure between the inlet tube and theautoclave. The polymerization was allowed to proceed for 1 hour whilepropylene was additionally introduced in a manner such that the totalpressure was kept constant. The polymerization was terminated byintroducing 20 ml of methanol from the inlet tube for materials. Then,the temperature was lowered and the pressure was released. The contentwas taken out into 2 liters of methanol and, after filtration and dryingin vacuo, a polymer was obtained. The results are shown in Table 1.

Example 6

The same procedures as those conducted in Example 5 were conductedexcept that triethylaluminum C (the content of aluminum hydride: 0.004%by weight) was used. The results are shown in Table 1.

Comparative Example 3

The same procedures as those conducted in Example 1 were conductedexcept that triethylaluminum A (the content of aluminum hydride: 0.6% byweight) was used. The results are shown in Table 1.

In Examples 5 and 6 and Comparative Example 3, the same amount ofdiethylzinc was used but the obtained intrinsic viscosity as theindicator of the molecular weight was different. In Comparative Example3, sufficient fluidity could not be obtained since the intrinsicviscosity was greater, i.e., the molecular weight was greater, thanthose in Examples 5 and 6.

TABLE 1 Example Comparative Example 1 2 3 4 5 6 1 2 3 Content ofaluminum 0.05 0.05 0.004 0.004 0.05 0.004 0.6 0.6 0.6 hydride (% byweight) Amount of diethylzinc 0.5 1.0 0.5 1.0 1.0 1.0 0.5 1.0 1.0(mmole) Yield (g) 570 590 670 640 57 68 680 830 51 Intrinsic viscosity(dl/g) 1.04 0.91 1.00 0.89 0.59 0.55 1.11 1.03 1.67 Fluidity (MFR) (g/10min) 93 142 85 143 60 86 Stereoregularity (mmmm) 98.2 98.3 98.2 98.298.2 98.4 98.1 98.4 98.1 (% by mole)

Example 7

Into an autoclave made of stainless steel, having an inner volume of 5liters and equipped with an inlet tube for materials and a stirrer, 30 gof homopolypropylene was placed as the seed powder. After the inside ofthe autoclave was sufficiently dried under a reduced pressure, thetemperature inside the autoclave was raised to 80° C. under stirring.Hydrogen and propylene were introduced so that the partial pressure ofhydrogen was adjusted to 0.6 MPa and the total pressure was adjusted to2.8 MPaG. Into the inlet tube for materials, 20 mmole of dehydratedn-heptane, 3.6 mmole of triethylaluminum and 1.0 mmole of diethylzincwere placed. These materials were then introduced into the autoclaveutilizing the difference in the pressure between the inlet tube and theautoclave. Into the inlet tube for materials, 20 ml of dehydratedn-heptane, 0.4 mmole of triethylaluminum, 1.0 mmole ofdicyclopentyldimethoxysilane and the preliminarily polymerized catalystobtained in Example 1 in an amount such that the amount of titanium was0.02 mmole were placed. These materials were then introduced into theautoclave utilizing the difference in the pressure between the inlettube and the autoclave. The polymerization was allowed to proceed for 1hour while propylene was additionally introduced in a manner such thatthe total pressure was kept constant (the first stage polymerization).After the temperature was lowered and the pressure was released, a smallamount of the product was taken out. The pressure in the autoclave wasreduced and the temperature was raised to 60° C. Hydrogen was added sothat the pressure was adjusted to 0.1 MPaG. A mixed gas containingethylene and propylene in amounts such that the ratio of the amounts bymole of ethylene to propylene was 3.5:6.5 was introduced and the totalpressure was adjusted to 1.5 MPaG. The polymerization was allowed toproceed for 45 minutes (the second stage polymerization) Then, thetemperature was lowered and the pressure was released. The product wastaken out and dried in vacuo and a block copolymer of propylene wasobtained. The obtained results are shown in Table 2.

Example 8

The same procedures as those conducted in Example 7 were conductedexcept that diethylzinc was used in an amount of 6.0 mmole. The resultsare shown in Table 2.

Comparative Example 4

The same procedures as those conducted in Example 7 were conductedexcept that diethylzinc was not used. The results are shown in Table 2.

Example 9

The same procedures as those conducted in Example 7 were conductedexcept that hydrogen was not introduced in the second stagepolymerization. The results are shown in Table 2.

Example 10

The same procedures as those conducted in Example 8 were conductedexcept that hydrogen was not introduced in the second stagepolymerization. The results are shown in Table 2.

Example 11

The same procedures as those conducted in Example 9 were conductedexcept that 1.0 mmole of ethanol was added at the start of the secondstage polymerization. The results are shown in Table 2.

Comparative Example 5

The same procedures as those conducted in Example 9 were conductedexcept that diethylzinc was not used. The results are shown in Table 2.

TABLE 2 Com- Com- para- para- tive tive Exam- Exam- Example ple Exampleple 7 8 4 9 10 11 5 Amount of diethylzine 1.0 6.0 0.0 1.0 6.0 1.0 0.0(mmole) Activity (tg/g-Ti) 810 820 680 1050 1150 780 790 Intrinsicviscosity of 1.04 0.90 1.17 1.00 0.94 1.01 1.24 homopolymer portion(dl/g) (Portion soluble in p-xylene) Intrinsic viscosity (dl/g) 2.352.18 2.80 4.17 4.09 5.72 5.68 Amount of soluble portion 18.4 18.1 18.318.6 14.8 12.6 15.3 (% by weight) Content of ethylene unit 29.0 29.729.7 30.5 27.4 31.4 28.7 (% by weight)

INDUSTRIAL APPLICABILITY

In accordance with the first invention of the present invention, anα-olefin polymer having extremely high stereoregularity, exhibitingexcellent fluidity and containing a decreased amount of catalystresidues can be obtained industrially advantageously.

In accordance with the second invention, a block copolymer of propylenewhich has a homopolymer portion exhibiting excellent fluidity and acopolymer portion having a high molecular weight can be efficientlyproduced.

1. A process for producing an α-olefin polymer which compriseshomopolymerizing an α-olefin or copolymerizing two or more α-olefins inthe presence of (A) a solid catalyst component comprising a magnesiumcompound, a titanium compound, a halogen and a silicon compoundrepresented by general formula (IV),Si(OR¹⁶)_(q)X² _(4-q)  (IV) (B) an organoaluminum compound having acontent of hydroaluminum compound of 0.1% by weight or less and (C) anorganozinc compound, wherein R¹⁶ represents a hydrocarbon group, X²represents a halogen and q represents an integer of 0 to
 3. 2. Theprocess according to claim 1, wherein the solid catalyst component (A)further comprises an electron-donating agent.
 3. The process accordingto claim 1, wherein the organozinc compound (C) is an organozinccompound represented by the formula:ZnR¹R² wherein R¹ and R² each independently represent a hydrocarbongroup having 1 to 10 carbon atoms.
 4. The process according to claim 1,wherein said homopolymerizing or said copolymerizing is conducted in thepresence of (D) an electron-donating compound.
 5. The process accordingto claim 1, wherein the organoaluminum compound (B) has a content ofhydroaluminum compound of 0.01% by weight or less.
 6. A process forproducing a block copolymer of propylene which comprises polymerizing afirst propylene in the presence of (A) a solid catalyst componentcomprising a titanium compound, an electron-donating agent, and asilicon compound represented by general formula (IV),Si(OR¹⁶)_(q)X² _(4-q)  (IV) (B) an organoaluminum compound and (C) anorganozinc compound to produce a crystalline polypropylene and thencopolymerizing a second propylene and at least one additional monomerselected from the group consisting of ethylene and α-olefins, having 4or more carbon atoms, in the presence of the crystalline polypropylenewherein R¹⁶ represents a hydrocarbon group, X² represents a halogen andq represents an integer of 0 to
 3. 7. The process according to claim 6,wherein the solid catalyst component (A) further comprises a magnesiumcompound.
 8. The process according to claim 6, wherein said polymerizinga first propylene is conducted in the presence of (D) anelectron-donating compound.
 9. The process according to claim 8, whereinthe electron-donating compound is an organosilicon compound.
 10. Theprocess according to claim 8, wherein the solid catalyst component (A)is produced by the process comprising: contacting the titanium compoundand a magnesium compound in the presence of the electron-donating agentat a temperature of 120 to 150° C. and washing an obtained product withan inert solvent at a temperature of 100 to 150° C.
 11. The processaccording to claim 10, wherein the solid catalyst component (A) isproduced by the process comprising: contacting the titanium compound andthe magnesium compound in the presence of the electron-donating agentand a silicon compound at a temperature of 120 to 150° C. and washing anobtained product with an inert solvent at a temperature of 100 to 150°C.
 12. The process according to claim 6, wherein the organozinc compound(C) is an organozinc compound represented by the formula:ZnR¹R² wherein R¹ and R² each independently represent a hydrocarbongroup having 1 to 10 carbon atoms.
 13. The process according to claim 6,wherein (E) an electron-donating substance is added before or duringsaid copolymerizing a second propylene and at least one additionalmonomer.
 14. A process for producing an α-olefin polymer according toclaim 1, wherein the solid catalyst comprises a titanium compoundrepresented by formula (II)TiX¹ _(n)(OR⁷)_(4-p)  (II) wherein X¹ represents a halogen atom, R⁷represents a hydrocarbon group which may be a saturated group or anunsaturated group, may be a linear group, a branched group or cyclicgroup and may have hetero atoms, p represents an integer of 0 to
 4. 15.A process for producing a block copolymer of propylene according toclaim 6, wherein the solid catalyst comprises a titanium compoundrepresented by formula (II)TiX¹ _(n)(OR⁷)_(4-p)  (II) wherein X¹ represents a halogen atom, R⁷represents a hydrocarbon group which may be a saturated group or anunsaturated group, may be a linear group, a branched group or cyclicgroup and may have hetero atoms, p represents an integer of 0 to
 4. 16.A process for producing an α-olefin polymer according to claim 3,wherein the solid catalyst comprises a titanium compound represented byformula (II)TiX¹ _(n)(OR⁷)_(4-p)  (II) wherein X¹ represents a halogen atom, R⁷represents a hydrocarbon group which may be a saturated group or anunsaturated group, may be a linear group, a branched group or cyclicgroup and may have hetero atoms, p represents an integer of 0 to
 4. 17.A process for producing a block copolymer of propylene according toclaim 12, wherein the solid catalyst comprises a titanium compoundrepresented by formula (II)TiX¹ _(n)(OR⁷)_(4-p)  (II) wherein X¹ represents a halogen atom, R⁷represents a hydrocarbon group which maybe a saturated group or anunsaturated group, may be a linear group, a branched group or cyclicgroup and may have hetero atoms, p represents an integer of 0 to 4.